Hi @cjenkinson @dennisserras
My apologies, I did not see this thread before now.
Let me preface my answer by saying that I do not know as much as I should on Shot(gun|Grid) Desktop, or which version maps to what capabilities, and how DCCs are leveraging it. So my answer will be a theoretical one, and reality often sees things differently.
The support for Autodesk Identity in the Desktop (when a QApplication exists) is leveraging what was done for the Single Sign-On support. Meaning that a web-browser-like window appears when you log on. That has been in place for a few years.
The original SSO-enabled version of Desktop was 1.5.0, but those first few versions had quirks and should probably be avoided.
Unfortunately, to properly answer the question the only sure way is to test it.
Not really a definitive answer, my apologies.